- Any mother (18-45 years of age) who presents to her obstetrician or midwife at the Medical University of SC (MUSC), Charleston, SC obstetrical facilities within the first 14 weeks after her last menstrual period (LMP) with confirmation of a singleton pregnancy will be eligible for enrollment in the study. Mothers of diverse ethnic backgrounds (African-American, Asian, Caucasian and Hispanic) will be actively recruited.